How to access the VM created by docker's HyperKit?

Update 2019-01-31, thanks to ru10's update, now there is a better way:

screen ~/Library/Containers/com.docker.docker/Data/vms/0/tty

Original Answer:

After a while, I found following way to get a shell of the VM that was created by HyperKit:

Run from terminal:

screen ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/tty

You will see an empty screen, then type enter, you will get a login prompt. Login as root and hit enter, you will get a shell (no password), you will gett the shell:

To exit the session, type Ctrl-A k (then y to confirm).

It is a little bit hacky, but it seems to work for now (Sep 2016) (Sep 2017).

Mac OS High Sierra Docker version 18.06.0-ce-mac70 (26399)

screen ~/Library/Containers/com.docker.docker/Data/vms/0/tty

instead of

screen ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/tty

According to this GitHub issue comment by a Docker maintainer, the recommended way to access the VM is through a privileged docker container.

Try logging into the VM: (I recommend this instead of using screen on the TTY)

$ docker run -it --privileged --pid=host justincormack/nsenter1